2 * mlt_transition.c -- abstraction for all transition services
3 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
4 * Author: Charles Yates <charles.yates@pandora.be>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software Foundation,
18 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
23 #include "mlt_transition.h"
24 #include "mlt_frame.h"
30 /** Forward references.
33 static int transition_get_frame( mlt_service
this, mlt_frame_ptr frame
, int index
);
38 int mlt_transition_init( mlt_transition
this, void *child
)
40 mlt_service service
= &this->parent
;
41 memset( this, 0, sizeof( struct mlt_transition_s
) );
43 if ( mlt_service_init( service
, this ) == 0 )
45 service
->get_frame
= transition_get_frame
;
51 /** Get the service associated to the transition.
54 mlt_service
mlt_transition_service( mlt_transition
this )
59 /** Connect this transition with a producers a and b tracks.
62 int mlt_transition_connect( mlt_transition
this, mlt_service producer
, int a_track
, int b_track
)
64 int ret
= mlt_service_connect_producer( &this->parent
, producer
, a_track
);
67 this->producer
= producer
;
68 this->a_track
= a_track
;
69 this->b_track
= b_track
;
76 /** Set the in and out points.
79 void mlt_transition_set_in_and_out( mlt_transition
this, mlt_timecode in
, mlt_timecode out
)
85 /** Get the index of the a track.
88 int mlt_transition_get_a_track( mlt_transition
this )
93 /** Get the index of the b track.
96 int mlt_transition_get_b_track( mlt_transition
this )
101 /** Get the in point.
104 mlt_timecode
mlt_transition_get_in( mlt_transition
this )
109 /** Get the out point.
112 mlt_timecode
mlt_transition_get_out( mlt_transition
this )
117 /** Process the frame.
120 static mlt_frame
transition_process( mlt_transition
this, mlt_frame a_frame
, mlt_frame b_frame
)
122 if ( this->process
== NULL
)
124 if ( !mlt_frame_is_test_card( a_frame
) )
126 mlt_frame_close( b_frame
);
131 mlt_frame_close( a_frame
);
137 return this->process( this, a_frame
, b_frame
);
141 /** Get a frame from this filter.
143 The logic is complex here. A transition is applied to frames on the a and b tracks
144 specified in the connect method above. Since all frames are obtained via this
145 method for all tracks, we have to take special care that we only obtain the a and
146 b frames once - we do this on the first call to get a frame from either a or b.
148 After that, we have 3 cases to resolve:
150 1) if the track is the a_track and we're in the time zone, then we need to call the
151 process method to do the effect on the frame (we assign NULL to the a_frame and
152 b_frames here) otherwise, we pass on the a_frame unmolested;
153 2) if the track is the b_track and we're the in the time zone OR the b_frame is NULL,
154 then we generate a test card frame, otherwise we pass on the b frame unmolested;
155 3) For all other tracks, we get the frames on demand.
158 static int transition_get_frame( mlt_service service
, mlt_frame_ptr frame
, int index
)
160 mlt_transition
this = service
->child
;
162 // Fetch a and b frames together...
163 if ( ( index
== this->a_track
|| index
== this->b_track
) &&
164 ( this->a_frame
== NULL
&& this->b_frame
== NULL
) )
166 mlt_service_get_frame( this->producer
, &this->a_frame
, this->a_track
);
167 mlt_service_get_frame( this->producer
, &this->b_frame
, this->b_track
);
170 // Special case track processing
171 if ( index
== this->a_track
)
173 // Determine if we're in the right time zone
174 mlt_timecode timecode
= mlt_frame_get_timecode( this->a_frame
);
175 if ( timecode
>= this->in
&& timecode
< this->out
)
177 // Process the transition
178 *frame
= transition_process( this, this->a_frame
, this->b_frame
);
180 // Important - NULL both frames now so that we know they're done...
181 this->a_frame
= NULL
;
182 this->b_frame
= NULL
;
186 // Pass on the 'a frame' and remember that we've done it
187 *frame
= this->a_frame
;
188 this->a_frame
= NULL
;
192 if ( index
== this->b_track
)
194 if ( this->b_frame
== NULL
)
196 // We're *probably* in the zone and the a frame has been requested
197 *frame
= mlt_frame_init( );
201 mlt_timecode timecode
= mlt_frame_get_timecode( this->b_frame
);
202 if ( timecode
>= this->in
&& timecode
< this->out
)
204 // We're in the zone, but the 'a frame' has not been requested yet
205 *frame
= mlt_frame_init( );
209 // We're out of the zone, pass on b and remember that we've done it
210 *frame
= this->b_frame
;
211 this->b_frame
= NULL
;
219 return mlt_service_get_frame( this->producer
, frame
, index
);
223 /** Close the transition.
226 void mlt_transitition_close( mlt_transition
this )
228 if ( this->close
!= NULL
)
231 mlt_service_close( &this->parent
);